1. lift the bottle of BTB solution 2. add BTB solution to 3 empty glass bottles 3. go to the lake and catch a black horse 4. put the black horse into the 2 vials of BTB solution 5. close the lids of the vials with BTB solution 6. cover one of the vials of BTB solution with the black horse with a black tin to prevent sunlight from getting through 7. observe the changes that occur after a day or so 8. remove the black tub 9. observe three bottles of BTB solution alone and three bottles of BTB solution with black horse, one covered and one uncovered by the black canister
<Conclusion Understand the change in color of the BTB solution Yellow when there is a lot of carbon dioxide Normal green color Blue when there is a lot of oxygen