Pearson Edexcel (9-1) GCSE Combined Science & GCSE Biology core practical - light and photosynthesis

Pearson UK Educators

17 Feb 202103:27

Summary

TLDRIn this Core Practical video, Mr. Osman from Claremont High School in London guides viewers through an experiment exploring how light intensity impacts photosynthesis. Using algae balls and a hydrogen carbonate indicator, students measure pH changes at varying distances from a light source to observe the rate of photosynthesis. The setup includes a control group and a negative control, with results recorded and analyzed to understand the process better.

Takeaways

🌱 Photosynthesis is the process by which green plants and some organisms like algae use sunlight to produce glucose and oxygen from carbon dioxide and water.
🔬 This experiment aims to explore how light intensity affects the rate of photosynthesis.
🏫 Mr. Osman, a science teacher at Claremont High School in London, is conducting the experiment.
🌟 Chlorophyll, a green pigment, plays a crucial role in the photosynthesis process by absorbing sunlight.
🧪 The experiment requires a controlled lab environment, eye protection, and various materials like PU bottles, algae balls, and a lamp.
📏 Different distances between the algae and the lamp (30, 40, 50, and 60 centimeters) are used to investigate the effect of light intensity.
🌡️ A heat filter and a water-filled clear container are used to control for heat, ensuring the experiment focuses on light intensity.
🕒 A negative control is set up by covering one bottle in kitchen foil to create a dark environment for comparison.
⏱️ The experiment runs for 60 minutes or longer to observe changes in the algae solution.
📊 The pH of the solution in each bottle is recorded and compared using an indicator scale to measure the rate of photosynthesis.
📋 Data obtained from the experiment is analyzed to understand the relationship between light intensity and photosynthesis.

Q & A

What is the main topic of the Core Practical video presented by Mr. Osman?
-The main topic is the study of how light intensity affects the rate of photosynthesis.
What is photosynthesis and what role does chlorophyll play in it?
-Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize glucose and oxygen from carbon dioxide and water. Chlorophyll is the green pigment that helps in capturing sunlight for this process.
What materials are needed to carry out the experiment as described in the video?
-The materials needed include an area shielded from external light, eye protection, PU bottles and caps, a beaker of algae balls, a hydrogen carbonate indicator, a lamp with a heat filter, a meter ruler, a 10 milliliter measuring cylinder, kitchen foil, a stopclock, and a pipette.
What are the different distances between the algae and the lamp that Mr. Osman plans to investigate?
-Mr. Osman plans to investigate distances of 30, 40, 50, and 60 centimeters between the algae and the lamp.
How many algae balls should be added to each bottle during the experiment?
-10 to 15 algae balls should be added to each bottle.
What is the purpose of the heat filter in the experiment?
-The heat filter is used to filter out the heat from the lamp, ensuring that only light, not heat, affects the algae.
How is the negative control set up in the experiment?
-The negative control is set up by covering one bottle in kitchen foil to block all light, and placing it next to the bottle closest to the lamp.
How long should the lamp be turned on for the experiment?
-The lamp should be turned on for at least 60 minutes.
What is the method for comparing the results of the experiment?
-The colors of the solutions in the bottles are compared with an indicator scale, and the pH of the solution is recorded.
How is the change in pH per hour calculated for each bottle?
-The change in pH per hour is calculated using the equation provided in the video script and the pH values recorded.
What should the students use to explain the data obtained during the experiment?
-Students should use their knowledge of photosynthesis to explain the data obtained.

Outlines

00:00

🌿 Introduction to Photosynthesis Experiment

Mr. Osman introduces a Core Practical video from Claremont High School in London, focusing on the effect of light intensity on the rate of photosynthesis. Photosynthesis is described as the process by which green plants and certain organisms like algae use sunlight, carbon dioxide, and water to produce glucose and oxygen with the aid of chlorophyll. The necessary materials for the experiment are listed, including a shielded lab area, eye protection, PU bottles, algae balls, hydrogen carbonate indicator, a lamp with a heat filter, a meter ruler, measuring cylinder, a stopclock, and plastic forceps or a spoon. The experiment involves setting up different distances between the algae and the lamp, adding algae balls and indicator solution to the bottles, and establishing control variables with a heat filter and a dark control using kitchen foil. The experiment duration is set for 60 minutes or more to observe changes in pH, which are then recorded and analyzed in relation to photosynthesis.

Mindmap

Keywords

💡Photosynthesis

Photosynthesis is a vital biological process in which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose or other sugars. This process is fundamental to life on Earth as it provides the oxygen we breathe and the organic compounds that serve as the basis of the food chain. In the video, photosynthesis is the central theme, as the experiment aims to study how light intensity affects the rate of this process. The script describes how sunlight, along with carbon dioxide and water, is used with the help of chlorophyll to produce glucose and oxygen.

💡Light Intensity

Light intensity refers to the amount of light energy that falls on a given area. It is a crucial factor in photosynthesis, as it influences the rate at which plants can convert light energy into chemical energy. In the context of the video, the experiment is designed to explore how varying the distance between the light source (lamp) and the algae affects the rate of photosynthesis, thereby impacting the light intensity received by the algae.

💡Chlorophyll

Chlorophyll is a green pigment found in the chloroplasts of plant cells and is essential for photosynthesis. It absorbs light energy, particularly from the blue and red parts of the spectrum, and uses this energy to convert carbon dioxide and water into glucose and oxygen. The script mentions chlorophyll as the pigment that assists in the process of photosynthesis, highlighting its importance in the experiment.

💡Indicator

An indicator in chemistry is a substance that changes color in response to changes in the acidity or alkalinity of a solution. In the video, a hydrogen carbonate indicator is used to measure the change in pH of the solution within the bottles, which is a proxy for the rate of photosynthesis. The color change of the indicator provides a visual representation of the chemical changes occurring due to photosynthesis.

💡pH

pH is a measure of the acidity or alkalinity of a solution, with values ranging from 0 (highly acidic) to 14 (highly alkaline), and 7 being neutral. In the context of the video, the pH of the solution in the bottles is recorded to monitor the production of oxygen during photosynthesis, as an increase in pH indicates the release of oxygen, which makes the solution more alkaline.

💡Control Variable

A control variable is an element that is kept constant in an experiment to ensure that any observed effects can be attributed to the variable being tested. In the script, the heat filter is set up as a control to block the heat from the lamp, ensuring that the experiment's results are due to light intensity and not heat. Additionally, a negative control is established by covering one bottle in foil, placing it in the dark to compare with the light-exposed bottles.

💡Heat Filter

A heat filter in this context is a water-filled clear container that is used to filter out the heat from the lamp, ensuring that the experiment focuses on the effect of light intensity rather than heat. The script instructs setting up a heat filter between the lamp and the bottles to maintain a controlled environment for the experiment.

💡Negative Control

A negative control in an experiment is a setup that does not receive the treatment being tested, which helps to establish a baseline for comparison. In the video, a bottle covered in kitchen foil and placed in the dark serves as a negative control. This control is essential to compare against the bottles exposed to light to verify that any observed changes are due to light exposure and not other factors.

💡Algae Balls

Algae balls are a type of freshwater algae, often used in educational settings for experiments due to their ease of handling and visible response to environmental changes. In the video, algae balls are added to the bottles to serve as the organisms undergoing photosynthesis. The script specifies adding 10 to 15 algae balls to each bottle to initiate the experiment.

💡Experiment Duration

The duration of an experiment is the length of time over which observations and measurements are taken. In the script, the lamp is turned on for 60 minutes or longer to allow for sufficient time to observe and measure the effects of light intensity on the rate of photosynthesis. This duration is critical to ensure that any changes in pH or other variables are due to the experimental conditions and not simply short-term fluctuations.

💡Data Interpretation

Data interpretation involves analyzing and explaining the results obtained from an experiment. In the video, after recording the pH changes, students are encouraged to use their knowledge of photosynthesis to explain the data. This step is crucial for understanding the relationship between light intensity and the rate of photosynthesis and for drawing conclusions from the experiment.

Highlights

Introduction to the Core Practical video by Mr. Osman, a science teacher at Claremont High School in London.

Exploration of how light intensity affects the rate of photosynthesis.

Photosynthesis defined as the process of converting sunlight into glucose and oxygen using chlorophyll.

List of materials needed for the experiment including lab setup, safety gear, and specific equipment.

Selection of different distances between algae and lamp for the experiment.

Instructions on setting up the experiment with algae balls and indicator solution.

Use of a heat filter as a control variable in the experiment.

Setup of a negative control by covering one bottle in kitchen foil to simulate darkness.

Duration of the experiment set to 60 minutes or longer.

Comparison of bottle colors with an indicator scale to measure pH changes.

Recording of the pH of the solution in a suitable table.

Calculation of the change in pH per hour using a provided equation.

Explanation of the data obtained during the experiment using knowledge of photosynthesis.

Potential for further reflection on the Core Practical through additional questions provided by the teacher.

Emphasis on the importance of reflecting on the experiment's outcomes.

Highlighting the educational value of the experiment for understanding photosynthesis.