Today’s lesson Introduction to photosynthesis Photosynthesis 1 lab

Photosynthesis

All cells need energy to grow Some living things eat other things to get energy – Where do we get our energy? Food Some living things produce their own food – Like plants! – This process is called photosynthesis

Photosynthesis Plants use sunlight as a source of energy to turn carbon dioxide and water into carbohydrates (sugars) and oxygen. – Energy comes from the sun – Water is pulled in by the roots from the ground – Carbon dioxide is absorbed from the air through the leaves

Photosynthesis Carbon dioxide + water + solar energy → carbohydrates + oxygen This is how we get the oxygen we breathe!

Conducting Experiments

Next little while Over the next couple of classes we will be conducting a few experiments related to photosynthesis – Labs 1 and 2 we will do together – After that you will be doing an evaluation based on these labs So you need to know what you’re doing and how we conduct experiments!

Variables Variables: the condition that we are changing to see if it has an effect on our experiment Many things can affect the outcome of an experiment so to see if a particular condition (or change) causes an effect we try to only change one thing at a time (the variable or treatment) – We want to compare the changed situation to the non-changed situation (the control) – We call this controlling the experiment

Example I want to know if plants grow better with music. – How would I test this? Have 2 groups of plants: Group 1: let grow without music Group 2: let grow with music – Which is the control group? Group 1 – no change

Photosynthesis I Lab

Photosynthesis Carbon dioxide + water + solar energy → carbohydrates + oxygen This is how we get the oxygen we breathe!

Today’s lab Purpose: Show that plants require carbon dioxide in order to photosynthesize Hypothesis: If test tube A is carbonated water and test tube B is tap water, then test tube ____ will have more bubbles.

Today’s lab Analysis: 1.Which test tube is the control? Test tube B (tap water) – regular condition 3. Which test tube is the variable? Test tube A (carbonated water) – treatment, we changed the regular condition

Today’s lab Procedure: 1.Take 2 test tubes. Label them A and B. 2.Fill test tube A with 40ml of carbonated water 3.Fill test tube B with 40 ml of tap water Be SUPER careful not to contaminate the water or it will mess up your results! 4.Take 2 pieces of Elodea (100 mm long) and place 1 in each test tube 5.Install a lamp 100 mm away from the test tubes 6.Count the number of bubbles of oxygen that are produced during 5 min 7.Record the data 8.Repeat 10 min, 15 min and 20 min.

Report Draw the setup Fill in your results table Answer all the questions (Analysis & Conclusion) – You have to show me your work before you leave!